Transmit Scheme Adaptation for Wireless Data Transmissions

1. A method for transmitting data packets according to a selected transmit scheme having a transmission data rate, comprising: selecting a data packet transmit scheme from one of a plurality of ordered sets of transmit schemes wherein a total set of defined transmit schemes is distributed over the plurality of ordered sets based upon a logical ordering, and further wherein the ordered sets comprise transmit schemes that are arranged according to one of the transmission data rate and transmission robustness; transmitting one of a packet fragment or a packet using a signal configuration based upon the selected transmit scheme; receiving feedback comprising an indication of at least one of a successful transmission, an unsuccessful transmission, a signal quality indication and a channel quality indication; vertically adapting the transmit scheme within the current ordered set of transmit schemes wherein vertically adapting the transmit scheme comprises one of remaining on a currently selected transmit scheme within the current ordered set or selecting the next lower or next higher transmit scheme in the current ordered set to maximize a first transmission performance metric within the current ordered set; replacing the transmit scheme for some packets with a probe transmit scheme, wherein the probe transmit scheme is a transmit scheme from a different ordered set of the plurality of ordered sets, whereby the probe transmit scheme is given as an output argument based upon the currently chosen transmit scheme as input argument; and collecting success/failure statistics for each probe transmit scheme ordered set to determine if transmit schemes from an ordered set of the plurality of ordered sets improves transmission performance over the current ordered set, the determining further including comparing collected statistics between various probe ordered sets and horizontally adapting to one of the probe ordered sets when a specified transmission performance metric is met, whereby horizontally adapting means that the probe ordered set becomes the new currently chosen ordered set and that steps of vertically adapting starts again in the new currently chosen ordered set from a transmit scheme that is a function of the last currently chosen transmit scheme.

2. The method of claim 1 wherein selecting the transmit scheme includes setting a plurality of transmit parameters with specific parameter settings wherein the transmit parameters include at least one of a number of spatial streams, code rate, modulation type, antenna configuration, and OFDM guard interval length.

3. The method of claim 2 wherein the parameter settings for the number of spatial streams ranges from 1 to 100, wherein the code rate is one of 1/2, 2/3, 3/4 or 5/6, wherein the modulation type is one of BPSK, QPSK, 8-PSK, 16-QAM, 32-QAM, 64-QAM, 128-QAM or 256-QAM, wherein the antenna configuration includes at least one selected antenna of a plurality of antennas, and wherein the OFDM guard interval length is in the range of 50 nanoseconds to 2 micro-seconds.

4. The method of claim 2 wherein: the list of transmit parameters is partitioned in a first group of transmit parameters and a second group of transmit parameters; each ordered set is defined as a subset of transmit schemes from the total set of transmit schemes between which the parameter settings in the first group of transmit parameters coincide; and the transmit schemes within an ordered set are arranged in a logical order according to the transmission rate resulting from the parameter settings of the transmit parameters in the second group of transmit parameters.

5. The method of claim 4 wherein horizontally adapting comprises changing at least parameter setting in the first group of transmit parameters and optionally changing one or more parameter settings in the second group of transmit.

6. The method of claim 4 wherein vertically adapting comprises changing at least one parameter setting in the second group of transmit parameters and while holding the parameters settings in the first group of transmit parameters constant.

7. The method of claim 4 wherein the first group of transmit parameters comprises at least one of the number of spatial streams, the antenna configuration, and the OFDM guard interval length.

8. A method in a digital communication system for transmitting a sequence of data packets, comprising: selecting a transmit scheme for each packet from a multitude of available transmit schemes and receiving immediate feedback on the success/failure of each packet transmission wherein the multitude of transmit schemes are arranged in a plurality of ordered sets that each defines an order of the transmit schemes contained within; selecting a transmit scheme for packet transmissions and subsequently remaining on the currently selected transmit scheme within a currently selected ordered set or selecting an adjacent lower or higher transmit scheme in the ordered set to maximize a first transmission performance metric within the ordered set based on a specified vertical adaptation technique; replacing the transmit scheme for at least one packet with a probe transmit scheme, whereby the probe transmit scheme is given as output argument from a table lookup using the currently chosen transmit scheme as input argument; collecting success/failure statistics for each probe ordered set whereby probe ordered set's are the ordered set that probe transmit schemes are taken from; and comparing the collected statistics between various probe ordered set's and horizontally adapting to one of the probe ordered sets when a second transmission performance metric is met.

9. The method of claim 8 further including for the new currently selected ordered set, remaining on the new currently selected transmit scheme within a currently selected ordered set or selecting the next lower or higher transmit scheme in the ordered set to maximize the first transmission performance metric within the ordered set based on a vertical adaptation technique.

10. Apparatus to adapt a transmit scheme for data packet transmissions in wireless transceivers, comprising: a transmit scheme adaptation module that determines a transmit scheme of each outgoing packet by processing success/failure statistics of previously transmitted packets; logic that generates a number of ordered sets of transmit schemes, each containing a number of transmit schemes; probe mapping tables containing a list of target ordered sets and corresponding target transmit schemes for each transmit scheme in all ordered sets; a vertical transmit scheme control unit to determine, within a current ordered set of transmit schemes following a specified rate adaptation scheme to be used for on-going data transmissions based upon a currently chosen transmit scheme selected by the transmit scheme adaptation module; a process control unit operable to request one or more subsequent packets to be transmitted from a transmit module to a remote transceiver using one of the probe transmit schemes from the probe mapping table of the current ordered set of transmit schemes; an ordered set control unit operable to collect success/failure statistics of on-going data transmissions in the current ordered set of transmit schemes based upon feedback information from the remote transceiver and further operable to probe transmit schemes to derive quality measures for the current home ordered set and probe ordered set; and wherein the ordered set control unit is operable to abandon the current ordered set of transmit schemes and to transition to a new ordered set of transmit schemes based upon collected data when a quality of the target ordered set exceeds a specified threshold of the current home ordered set quality.